<?php

/**
 * Created by PhpStorm.
 * User: Administrator
 * Date: 2019/8/22
 * Time: 12:27
 */
class AES256加密
{

}
class aes {

    static public $mode = MCRYPT_MODE_NOFB;

    static public function generateKey($length=32) {
        if (!in_array($length,array(16,24,32)))
            return False;

        $str = '';
        for ($i=0;$i<$length;$i++) {
            $str .= chr(rand(33,126));
        }

        return $str;
    }

    static public function encrypt($data, $key) {

        if (strlen($key) > 32 || !$key)
            return trigger_error('key too large or key is empty.', E_USER_WARNING) && False;

        $ivSize = mcrypt_get_iv_size(MCRYPT_RIJNDAEL_256, self::$mode);
        $iv = mcrypt_create_iv($ivSize, (substr(PHP_OS,0,1) == 'W' ? MCRYPT_RAND : MCRYPT_DEV_URANDOM ));
        $encryptedData = mcrypt_encrypt(MCRYPT_RIJNDAEL_256, $key, $data, self::$mode, $iv);
        $encryptedData = $iv . $encryptedData;

        return base64_encode($encryptedData);
    }

    static public function decrypt($data, $key) {

        if (strlen($key) > 32 || !$key)
            return trigger_error('key too large or key is empty.', E_USER_WARNING) && False;

        $data = base64_decode($data);
        if (!$data)
            return False;

        $ivSize = mcrypt_get_iv_size(MCRYPT_RIJNDAEL_256, self::$mode);
        $iv = substr($data, 0, $ivSize);

        $data = substr($data, $ivSize);

        $decryptData = mcrypt_decrypt(MCRYPT_RIJNDAEL_256, $key, $data, self::$mode, $iv);

        return $decryptData;
    }}
